The Clean Teen Machine

The insulin pump that Nick attaches to his back has a tiny catheter that stabilizes the insulin level in his system. It's connected to a wireless device that Nick keeps in his jeans pocket; he checks it regularly to monitor his levels. Every day, he pricks his finger up to 12 times to check whether he needs to correct his blood-sugar level. It's become a daily routine, second nature.

"I'm obviously fine now, but when you learn about your diabetes, there's a thing called the honeymoon period," Nick says. "That's the time after you're diagnosed, and your blood sugar is a little all over the place." He says it took him nine months to feel like himself again. "Once you find a pattern with diabetes, you can have normalcy."

"I can't tell you how frustrating it is to hear people belittle diabetes because it's maintainable," says Kevin Sr. "They've never had to sit on a bus when a pump didn't work and a second pump didn't work — this was just last week — and a third didn't, and he had to give himself a shot when we're driving down a highway. Everybody on our team is on full alert, watching every move Nick makes on that stage every single night of his life."

After Nick's diagnosis would have been a good time for the Jonas Brothers to catch a break. But it didn't happen. Despite endless touring, Columbia Records called in early 2007 and said it was not releasing the band's second album.

"The reason given to us was 'The indicators were not there,'" says Kevin Sr. "It was devastating."

Still, even before the breakup with Columbia, the Jonases had caught the attention of Bob Cavallo, the chairman of Buena Vista Music Group and the former manager of acts like the Lovin' Spoonful, Earth, Wind and Fire, and an obscure Minneapolis R&B singer named Prince. Impressed by the JBs' musicianship, Cavallo brought them to Bob Iger, and the rest is Mouse House history. The Jonases' first album under Hollywood, Jonas Brothers, sold 1.4 million copies. Last year, the Jonas Brothers made a reported $12 million as a group. Recently, they signed a multimillion-dollar deal with Live Nation, the concert-sales company that also handles U2 and Madonna. The Jonas clan now lives in Los Angeles and just closed on a new spread in Dallas, not far from a posh country club.

"It's just like a random place to go on vacation," the young Kevin says. "It doesn't even feel real. I get in a golf cart, go straight to the course. They're like, 'Hey, Mr. Jonas, you going to play today?' It's the best thing ever."

The secret ingredient of the Jonas Brothers phenomenon? Oversharing. They may wear skinny jeans and narrow ties, but the boys reject the maxim that rock stars should always be cool. The band spends hours cranking out mundane homemade videos about everything from Joe's new headband to the food in the greenroom at The Oprah Winfrey Show. I watch a video of Joe whacking Nick over the head with a plastic baseball bat that had nearly 8 million viewers. On tour, they even show a Jumbotron video of Nick putting on his insulin pump. The clip gets a giant squeal, since there's also a quick peek at Nick's flesh. "I think we're editing that," Kevin Sr. says, shaking his head. "Not the right place for them to scream."

Then there are the Jonases' already famous meet-and-greets. Most bands do these — obligatory schmoozefests with sponsors, contest winners, friends of friends and local VIPs. But the Jonas Brothers take it to endurance extremes. In Dallas I watch them greet more than 400 fans in 99-degree heat.

"They are the new music business — work hard, touch your fans," Brad Wavra, a tan, hyper Live Nation VP, tells me as we watch the grip-and-grin in Dallas. "We know a band that used to count the number in their meet-and-greets — if it was 50, and there were 51 people there, they wouldn't meet that 51st kid."

"You got 300 people in the lobby of your hotel, that's not a problem," says Johnny Wright, a longtime boy-band maestro who also advises the JBs. "That's a blessing. Don't go through the back door. Go through the front."

So far, the Jonases embrace these rituals. They pay close attention to their meet-and-greets, noting the increasing number of older teenage girls in red dresses and heels (an outfit mentioned in the band's new single, "Burnin' Up"), and amorous moms. "The dads make jokes like, 'Keep your hands off my daughter,'" Nick says.

If there is one subject the Jonas Brothers are tired of talking about, it's their purity rings. One afternoon on the band's tour bus, where the fridge is stuffed with Diet Dr Pepper, Dibs ice cream treats and Smucker's Uncrustables PB&J sandwiches, I ask them about the silver bands, which are mentioned in nearly every press account of the brothers.

"We've talked about it enough," Nick says abruptly. "We'd rather focus on the music and the movie." I press a little harder. Why not talk about it? After all, their fans (and the parents) like the fact that they wear them. Everywhere I go in the crowds at concerts, girls show off their rings. A spokeswoman for James Avery Craftsman, a large Christian-based jeweler, tells me that sales of the company's "True Love Waits" purity ring are up 25 percent this year. "We can't say for sure why, but it's up," she says.

After my second attempt, Joe looks at Nick. "Go ahead," Joe says.